Answer:
cell wall
Explanation:
animal cells have cell membranes but not walls :)
The answer is:
readily bonds (because nickel's valence number is 2)
Answer:
They established of a postal system
The spread of weapons that used gunpowder
The extension of the grand canal in China
The invention of new medicines
Explanation:
The Pax Mongolica refers to the stabilizing impacts of the conquests of the Mongol Empire on the social, cultural and economic life of the citizens of the vast Eurasian territory that the Mongols conquered in the 13th and 14th centuries.